Lifting jack



Nov, 22, 1949 s. c. STEWART 2,489,056

LIFTING JACK Filed March 21, 1946 2 Sheets-Shget 2 2 BY wayraw d.

ATTURN EYB Patented Nov. 22, 1949 UNITED STATE T-ENT- OFFICE 2 Claims.The invention relates to a lifting jack andmore especially to. a wheeledtruck jack.

The primary. object of Ithe invention is the provision of a jack of thischaracter, wherein through a toggle acting lift mechanism upon a wheeledcarriage, a motor or other vehicle can be raisecl and lowered with easeand dispatch, the height of'liftingcan be-varied and the lift having amaximum range without any possibility of the jack turning over orbecoming unbalanced by its load under maximum lift range.

Another object of the invention is the provision of a jack of thischaracter, wherein the construction thereof is novel and the assembly ofthe parts unique, to assure the maximum of adjustment to give extremelifting heights thereto in the raising or hoisting of work.

A further object of the invention is the provision of a jack of thischaracter, wherein it is effective as a hoisting or lift crane, and isperfectly balanced at Variable heights or lift, it also being movablefrom one point to another as it is of the mobile type.

A still further object of the invention is the provision of a jack ofthis character, which is simple in construction, thoroughly reliable andeflicient in operation, strong, durable, readily and easily operated,possessed of few parts, compact in assembly, conveniently handled withdispatch, and inexpensive to manufacture.

With these and other objects in view the invention consists in thefeatures of construction, combination and arrangement of parts as willbe hereinafter more fully described, illustrated in the accompanyingdrawings, which disclose the preferred embodiment of the invention andpointed out in the claims hereunto appended.

In the accompanying drawings:

Figure l is a side view of the jack constructed in accordance with theinvention.

Figure 2 is a rear end view of the same.

Figure 3 is a view similar to Figure 1 showing the jack in an adjustedposition.

Figure 4 is a top plan view with the jack in position as shown in Figure1.

Figure 5 is a view similar to Figure 3 showing the jack in an adjustedposition.

Figure 6 is a plan view with the jack in the position shown in Figure 5.

Figure 7 is a fragmentary sectional view taken on the line 11 of Figure6.

Figure 8 is a sectional view taken on the line 8-8 of Figure 5 lookingin the direction of the arrows.

Figure 9 is a sectional view taken on the line the arrows.

2 9- 9 of' Figure 7 looking in the direction of the arrows.

Figure 10 is a sectional viewtaken on the line i m of Figure 3 looking.in the-directionof Similar reference characters indicate cor, respondingparts. throughout the several views in the drawing.

Referring. to the drawings in detail, the jack constructed in accordancewith the invention, comprises a wheeled carriage involving an elongatedor rectangular shaped horizontal sill or chassis frame It, having afront extension section ll, its wheels together with the wheels of theframe it being provided with traction and swiveled caster steeringwheels I2 and I3 respectively.

The frame It] at the end next to the wheels l3 has rising therefrom aperpendicular handle bar frame l4 having the cross handle rung l5 at anelevation.

At the longitudinal center of the frame l0 and at the end having thehandle bar frame I4 is a hydraulic lifter, its upright cylinder it isstationarily mounted on the frame I 0, while its movable lifting plungerll telescopes within this cylinder and is raised and loweredhydraulically under the control of an actuator hand lever l8. Theplunger I! at its upper end carries a crosshead l9 encasing at its outerends pulleys 20 over which are trained hoisting chains 2|, there being apair of these, and the same have coupling connections 22 with the frameIt] and also coupling connections 23 to a pair of vertically swingableand horizontally slidable beams 24, which are in spaced parallelrelation to each other. The beams 24 are joined near opposite ends bycross struts 25, one being a runner on a horizontal guide lodge or track26 built to the side sills of the frame it at their inner faces.

Arranged between the beams 24 and swingingly connected thereto by apivot 21 is a jacking rail 28, the pivot being intermediate withrelation to the length of such beams and the rail, and the latterconnected by a hinge 29 at its inner end to the frame it! next to theend of the latter adjacent to the steering casters thereof.

The outer end of this rail is equipped with a swivel rest fitting 30while telescopically engaged in such rail is slidable extension railsection 3|, which has an outer hook end 32 thereto, and by thisextension rail section the rail can be lengthened or shortened, as maybe required for vertical height lifting quality.

The rail 28 is provided at its outer end with an 3 underslung latchdevice 33 which can engage the frame ill to hold them together when in ahorizontal plane with one another, when the rail has been completelylowered on the marriage The height of swing of the lift rail 28 can bealtered by extending the rail section 3i, as best seen in Figure 5 ofthe drawings, while to prevent the tipping over of the carriage theframe extension section i I can be projected from the frame l0, so thatthe load will be properly balanced, this being also best seen in saidFigure 5. The lifter is operated to raise and lower the jacking rail 28and its extension rail section 3|, which is latched by the latch device33 in an extended position. To shorten the throw of the jacking railbeams 24 are automatically adjusted by the lifter, including thecylinder l6 and plunger l1 respectively.

What is claimed is:

1. A structure of the kind described, comprising a wheeled carriageincluding a pair of horizontally extending hollow side members ofrectangular cross section, vertically swingable and horizontallyshiftable hoisting beams on the carriage, a jacking rail pivoted to thecarriage and to the beams and regulated by movement of the latter, andan adjustable extension for the car riage including a pair of I-beamseach slidably mounted in one of said hollow members,

2. A structure of the kind described, comprising a wheeled carriageincluding a, pair of horizontally extending hollow side members ofrectangular cross section, vertically swingable and horizontallyshiftable hoisting beams on the carriage, a jacking rail pivoted to thecarriage and to the beams and regulated by movement of the latter, anadjustable extension for the carriage including a pair of I-beams eachslidably mounted in one of said hollow members, and an extensiblesection for the jacking rail and a latch for holding the same inadjusted positions.

SKILER C. STEWART.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 188,846 Bengger Mar. 27, 18771,410,103 Lightner et a1 Mar. 21, 1922 1,553,074 Engel Sept. 8, 1925FOREIGN PATENTS Number Country Date 342,488 Great Britain Feb. 5, 1931

